After an actual, factual bug report from a user, fixed include_directories so that it checks that the specified directories exist.

build.py

@@ -86,8 +86,8 @@ class IncludeDirs():
     def __init__(self, curdir, dirs, kwargs):
         self.curdir = curdir
         self.incdirs = dirs
-        # Fixme: check that the directories actually exist.
-        # Also that they don't contain ".." or somesuch.
+        # Interpreter has validated that all given directories
+        # actually exist.
         if len(kwargs) > 0:
             raise InvalidArguments('Includedirs function does not take keyword arguments.')
 

interpreter.py

@@ -1001,10 +1001,14 @@ class Interpreter():
         conf.mark_used()
 
     def func_include_directories(self, node, args, kwargs):
+        curdir = os.path.join(self.subproject, self.subdir)
+        absbase = os.path.join(self.environment.get_source_dir(), curdir)
         for a in args:
             if not isinstance(a, str):
                 raise InvalidArguments('Argument %s is not a string.' % str(a))
-        curdir = os.path.join(self.subproject, self.subdir)
+            absdir = os.path.join(absbase, a)
+            if not os.path.isdir(absdir):
+                raise InvalidArguments('Include dir %s does not exist.' % a)
         i = IncludeDirsHolder(curdir, args, kwargs)
         return i
 

test cases/failing/6 missing incdir/meson.build

@@ -0,0 +1,3 @@
+project('missing incdir', 'c')
+
+inc = include_directories('nosuchdir')